Alpha-acyloxyacetic acid production

ABSTRACT

A-ACYLOXYACETIC ACIDS ARE PRODUCED AS THE MAJOR PRODUCT BY THE REACTION OF FORMALDEHYDE, A CARBOXYLIC ACID AND CARBON MONOXIDE IN THE PRESENCE OF CATALYTIC AMOUNTS OF A GROUP VIII NOBLE TRANSITION METAL COMPOUND AND AN IODIDE PROMOTER.

United States Patent 3,751,453 ALPHA-ACYLOXYACETIC ACID PRODUCTIONVictor P. Kurkov, San Rafael, Seymour J. Lapporte,

Orinda, and William G. Toland, San Rafael, Califl, assignors to ChevronResearch Company, San Francisco, Calif. No Drawing. Filed Aug. 21, 1972,Set. N 282,516 Int. Cl. C07c 67/00 US. Cl. 260-494 12 Claims ABSTRACT OFTHE DISCLOSURE a Acyloxyacetic acids are produced as the major productby the reaction of formaldehyde, a carboxylic acid and carbon monoxidein the presence of catalytic amounts of a Group VIH noble transitionmetal compound and an iodide promoter.

DESCRIPTION OF THE PRIOR ART The preparation of a-acetoxypropionic acidfrom acetaldehyde, carbon monoxide and acetic acid in the presence ofacidic catalysts is disclosed in US. Pat. No. 2,265,945, issued on Dec.9, 1941, to D. J. Loder.

The preparation of a-hydroxyacetic acid (glycolic acid) fromformaldehyde, carbon monoxide and water in the presence of acidiccatalysts at high pressures and tern peratures is disclosed in Noller,Chemistry of Organic Compounds, page 743, 2nd ed., 1957, W. B. SaundersCo., Philadelphia, Pa.

DESCRIPTION OF THE INVENTION The catalyst system The catalyst systememployed in the process of the present invention comprises a rhodiumcompound and an iodide promoter.

Examples of suitable rhodium compounds include rhodium halides, such asRhCl RhBr and Rhlg; rhodium carbonyl halides, such as Rh (CO) Br Rh(CO),Cl and Rh (CO),I and Rh O Other suitable rhodium compounds arerhodium coordination compounds containing monodentate ligands, such ascarbon monoxide, halides, amines, organophosphines, organoarsines and/ororganostibines, i.e., rhodium compounds such as Rh[(C H l (CO)I and Thepreferred rhodium compounds are rhodium halide and rhodium carbonylhalide compounds.

Suitable iodide promoters include iodine, hydrogen iodide (hydroiodicacid) and alkyl iodides of 1 to 6 carbon atoms and 1 to 3 iodide groupssuch as methyl iodide, ethyl iodide, methylene diiodide, iodoform, andisopropyl iodide.

Certain rhodium compounds such as RhI[(C H P] and Rhlg incorporateiodide moieties so that a separate iodide promoter may not be required.

The catalyst system of a rhodium compound and an iodide promoter is aknown catalyst combination and is disclosed, for example, in US.3,579,551 issued to Craddock et al. on May 18, 1971. The disclosures ofthis patent are hereby incorporated by reference.

Molar ratios of the iodide promoter to the rhodium component of thecatalyst system in the range of 1:1 to 2S00z1 are generally suitable.However, the preferred molar ratios of iodide promoter to rhodiumcomponent are about 3 :1 to 300:1 and the most preferred molar ratiosare about 5:1 to 100:1.

Concentrations of the rhodium compound of the catalyst system in thereaction medium between 10* moles/ liter and 10 moles/ liter, arenormally employed, with the preferred range being 10- moles/liter to 10-moles/ liter. Higher concentrations even to the extent of 1 mole/ litermay, however, be used if desired.

The concentration of the iodide promoter portion of the catalyst systemin the reaction medium may vary widely over the broad concentrationrange of l0 mole/ liter to 18 moles/liter, based on iodide atom. In theprocess of this invention, however, the preferred concentration range ofpromoter is 10' moles/liter to 2 moles/ liter.

Although the catalyst system is generally employed as a homogeneouscatalyst system, components of the catalyst system, e.g., the rhodiumcompound, may be dispersed on inert supports, such as silica or alumina,to provide a heterogeneous catalyst system.

The formaldehyde reactant The formaldehyde reactant is suitablyintroduced in the pure form or produced in situ, e.g., fromparaformaldehyde or trioxane. In the preferred modification of theprocess, the formaldehyde is provided in the form of trioxane.

The carboxylic acid reactant The process of the invention is applicableto aliphatic and aromatic carboxylic acids of from 1 to 10 carbon atoms.

Preferred carboxylic acid reactants comprise alkanoic acids of 1 to 10carbon atoms, dialkanoic acids of 3 to 10 carbon atoms, haloalkanoicacids of 1 to 10 carbon atoms and of 1 to 5 halogens of atomic numbersfrom 9 to 35 (fluorine, chlorine and bromine) and hydrocarbon aromaticacids of 7 to 10 carbons and 1 to 2 carboxy groups. The most preferredcarboxylic acid reactants are alkanoic acids of 2 to 6 carbon atoms,especially acetic and propionic acids.

Representative alkanoic acids include formic, propionic, butyric,isobutyric, Valerie, hexanoic, heptanoic, octanoic, decanoic, etc.Representative dialkanoic acids include malonic acid, succinic acid,adipic acid, etc. Representative haloalkanoic acids includetrifluoroacetic, trichloroacetic, tribrornoacetic,flfifi-trichloropropionic acid, perchloropropionic acid,B-chloropropionic acid, p-bromopropionic acid, etc. Representativearomatic acids include benzoic, p-toluic acid, 2,4-dimethylbenzoic acid,o-phthalic acid, isophthalic acid, terephthalic acid, etc.

The a-acyloxyacetic acid product The net reaction of the process of theinvention is depicted in Equation 1.

ll R( J0H 011.0 co noocrnooni wherein 0 O O I II I HOC'l-R-C 0 (31120 011 HOzOOHzO-R- OCH C 0 H R(EOH):1

represents the dicarboxylic acid reactant.

wherein Illustrative a-acyloxyacetic acid product includesaformyloxyacetic acid, a-acetoxyacetic acid, a-(trichloroacetoxy) aceticacid, bis-(carboxymethyl) adipic acid ester, monocarboxy methyl adipicacid ester, a-propionyl- In certain modifications wherein a supportedrhodium catalyst is employed, the reaction is effected in a continuousmanner as by passing a mixture of the reaction components and theremaining catalyst components oxyacetic acid, a-butyryloxyacetic acid,a-valeroyloxy- 5 through a reactor in which the supported transitionmetal acetic acid, a-hexanoyloxyacetic acid, a-decanoyloxyaceticcatalyst is maintained. acid, a-benzoyloxyacetic acid, a-(p-toluoyloxy)-acetic The process of the invention is conducted atmoderate acid, bis-(carboxymethyl) phthalic acid ester,monocartemperatures and pressures. Suitable reaction temperaturesboxymethyl phthalic acid ester, etc. varying from about 100 C. to 300 C.are satisfactory and reaction temperatures varying from about 150 C. Thereactant condltlons to 250 C. are preferred. The process is conducted ator The reactants p y in the p of the mventlon above atmosphericpressure, and pressures from about 1 are generally contacted in themolar ratios defined by the atmosphere to about 200 atmospheres aresatisfactory stoichiometry of Equation That the molar of At theconclusion of the reaction, the product mixture is carboxylic acid toformaldehyde is substantially eqmmolar Separated and the wacyloxyaceticacid product is 15:1 to 1:15) and the of Farbon covered by conventionalmeans such as fractional distil oxide to formaldehyde is substaqtlallyeq lation. Unreacted reaction components are suitably re- 1511 to Forcarboxyhc aclds havlng two carboxy cycled for further use in theprocess. In addition to the groups an additional molar amount offormaldehyd? and a-acyloxyacetic acid product, the process of theinvention carbon monoxide may be employed, e molar l'atlos of alsoproduces major amounts of methylene bisacetate carboxylic acid toformaldehyde or carbon monoxide are 0 0 about 1.5 :2 to 1:25. However,an excess of any reactant g a is suitably employed. For example, in somemodifications 3 OCH2O 0H3 of the process, it is desirable to employexcess carboxylic nd/ oxymethylene bisacetate acid and/or carbonmonoxide as reaction diluents. Ac- O O cordin 1 molar ratios ofcarboxylic acid to formaldehyde of fror n 10:1 to 1:10 are satisfactory,although molar CHigOCHtOCHaO ratios of from 5:1 to 1:2 are preferred;and molar ratios Examples of carbon monoxide to formaldehyde of from10:1 to v 1:10 are satisfactory, although molar ratios of from 5:1 The RP of f y y e a}e1ds to 1:1arepreferred toxyacetic acid and o-propionyloxyacetic acld) was car- The process of the invention isconducted in a fluid Tied out by the followlng p l phase, i.e., eitherin the gaseous or liquid phase, in the A11 autoclave ehafged Wlth thel'hodlum Catalyst, presence or in the absence of an inert reactiondiluent. seeled and fillshed wlth nltfog en followed y carbon Suitableinert normally liquid diluents are hydrocarbons oXlde- The alkanolefield, lodlde Promoter, follllaldehyde free from aliphatic unsaturationsuch as hexane, heptane, Were then d d to the autoclave. The autoclaveyvas octane, decane, cyclohexane, benzene, toluene and xylene. Sealedand Pressured Wlth Carbon monoXlde and p y Suitable normally gaseousdiluents are nitrogen, hydrogen, ted to reaction temperature. argon, hli th nd th A i di at d ab After maintaining the reaction at reactiontemperature in some modifications of the process, a portion of the car-40 for the indicated reaction time, the autoclave was opened bonmonoxide or carboxylic acid reactant suitably serves and the reaetiollmiXfllre analyled y nuclear magnetic as the reaction diluent. Whendiluent is employed, up to resonance spectroscopy, infrared spectroscopyand gasabout moles per mol of formaldehyde reactant are liquidchromatography. satisfactory. The process is suitably conducted in aninert The reactant, the catalyst components, the reaction reactionenvironment so that the presence of reactive ma- 45 conditions employed,and the yield of products (based on terials such as oxygen is desirablyavoided. trioxane charged) are tabulated in Table I.

TABLE I Run number 1 2 a 4 5 6 7 s 9 kii'l'iict%%i2a::: $5255: 22%;:31535.1: ififirzaraasx: $3555; (1 Zmol X35551: 33355:: $53313: 313552,.Iodide promoter (0.05 mol HI"--- CHaIm- HI CHaI (0.0125 mol)-.- CHzI...None GILL..- H1. HzSO4; Rh(oo)=o1 0.001-.- 0 001-... 0.001--. 0.000250.001 0. 001..- None Non New Carbon monoxide (initial p.s.i.g) 1, 1,1,000..- 10 1,000.- 1,000--.. 1,000.... 1, 000. 1,000. Temperature 0.)150..... 150...... 125.-... 140 150 150"--- 150 150- 150. Time (hours) 5a 1s 17.5 5 5 5 5 Percent yield a-acetoxyaeetic acid 68 42 R 47(aglgipcgonyloxy 0 0 45 23 Percent yield methylene 4 0 a 22 15(meitglnyalgge bispro- 6 6.5 a 5. Percent yield oxymethylene bisaeetste83 p 0 0,- 0

What is claimed is:

The process of the invention is carried out by intimately contacting theformaldehyde, carboxylic acid and carbon monoxide in the presence of thetransition metal catalyst and iodide promoter. A variety of procedurescan be employed for contacting the reaction components with the catalystsystem. In one modification, the entire amounts of formaldehyde,carboxylic acid, carbon monoxide and catalyst components are charged toan autoclave or similar pressure reactor and maintained at reactionconditions for the desired reaction period. In another modification anactive catalyst system is initially preformed by contacting at elevatedtemperature the rhodium compound, carbon monoxide, and iodide promoterin a suitable solvent and Subse uently add ng the remaining reactioncomponents.

1. A process of producing a-acyloxyacetic acid which comprises reactingformaldehyde, carbon monoxide and a carboxylic acid selected fromalkanoic acids of l to 10 carbon atoms, dialkanoic acids of 3 to 10carbon atoms, haloalkanoic acids of 1 to 10 carbon atoms and 1 to 5halogens of atomic number 9 to 35 and hydrocarbon aromatic acids of 7 to10 carbon atoms and 1 to 2 carboxy groups in the presence of catalyticamounts of a rhodium compound and an iodide promoter, the molar ratio ofcarboxylic acid to formaldehyde being from about 1:10 to 10:1, at atemperature of from about 50 C. to 300 C. and a carbon monoxide partialpressure of from about 1 p.s.i.a. to 2000 p.s.i.a.

2. The process of claim 1 wherein the carboxylic acid is an alkanoicacid.

3. The process of claim 2 wherein the rhodium compound is a rhodiumcarbonyl halide.

4. The process of claim 2 wherein the alkanoic acid has from 2 to 6carbon atoms.

5. The process of claim 4 wherein the molar ratio of carbon monoxide toformaldehyde is from 5:1 to 1:1 and the molar ratio of alkanoic acid 00formaldehyde is 5:1 to 1:2.

6. The process of claim 4 wherein the reaction temperature is 100 to 250C.

7. The process of claim 6 wherein the alkanoic acid is acetic acid orpropionic acid.

8. The process of claim 7 wherein the rhodium compound is RH(CO) Cldimer.

9. The process of claim 7 wherein the formaldehyde is provided in theform of trioxane.

10. The process of claim 4 wherein the iodide promoter is hydroiodicacid or an alkyl iodide.

11. The process of producing a-alkanoyloxyacetic acid which comprisesreacting formaldehyde, carbon monoxide and an alkanoic acid of 1 to 10carbon atoms in the presence of catalytic amounts of a rhodium compoundand hydroiodic acid, the molar ratio of alkanoic acid to formaldehydebeing from about 1:10 to 10:1, at a temperature of from about 50 C. to300 C. and a carbon monoxide partial pressure of from about 1 p.s.i.a.to 2000 p.s.i.a.

12. The process of claim 11 wherein the alkanoic acid is acetic acid.

References Cited UNITED STATES PATENTS 2,211,624 8/1940 Loder et a1260494 VIVIAN GARNER, Primary Examiner U.S. Cl. X.R.

260408, 410.9 R, 475 R, 476 R, 485 R, 487

